STG global TANVAC HDV3000, Operator'S Manual

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Reference Information
Section
Engine Ratings
i00727327
Engine Rating Conditions
SMCS Code: 1000
All engine ratings are in compliance with the following
standard ambient air conditions of “SAE J1349”:
• 99 kPa (29.3 inches of Hg)
• 30 percent relative humidity
• A temperature of 25 °C (77 °F)
Ratings relate to the standard conditions of
“ISO8665”, of “ISO3046/1”, of “DIN6271”, and of
“BS5514”.
The engine ratings are based on the following fuel
specifications:
• Low heat value (LHV) of the fuel of 42 780 kJ/kg
(18,390 Btu/lb) at 29 °C (84 °F)
• Gravity (API) of 35 degrees at 15 °C (60 °F)
• Specific gravity of .849 at 15 °C (60 °F)
• Density of 850 kg/m
3
(7.085 lb/US gal)
The engine ratings are gross output ratings.
Gross Output Ratings – The total output capability
of the engine that is equipped with standard
accessories.
Standard accessories include the following
components:
• Oil pumps
• Fuel pumps
• Water pumps
Subtract the power that is required to drive auxiliary
components from the gross output. This will produce
the net power that is available for the external load
(flywheel).
i00819749
Engine Rating Definitions
SMCS Code: 1000
It is important to know the use of the engine so that
the rating will match the operating profile. The proper
rating selection is also important so that the
customer's perception of price and value is realized.
In selecting a rating for a specific application, the
most important consideration is the time that is spent
at full throttle. These rating definitions identify the
percent of time at full throttle. The definitions also
identify the corresponding times below rated rpm.
Note: The examples of the applications are only for
reference. For an exact determination of the
appropriate rating, follow the OEM specifications or
consult your Caterpillar dealer.
A Rating – This rating is used for heavy-duty
applications that are operated at rated load and at
rated rpm up to 100 percent. This rating is used for
engines that operate without interruption of load
cycling. Typical applications include the following
examples: pipeline pumping and ventilation.
B Rating – This rating is used when power and/or
rpm are cyclic. The engine should be run at full load.
The engine should not exceed 80 percent of the duty
cycle. Typical applications include the following
examples: irrigation, operation where normal pump
demand is 85 percent of the engine rating, oil
pumping/drilling, field mechanical pumping/drilling
and stationary/plant air compressors.
C Rating – This rating is used when power and/or
rpm are cyclic. The horsepower and the rpm of the
engine can be utilized continuously for one hour. This
is followed by one hour of operation at the A rating or
below the A rating. The engine should be run at full
load. The engine should not exceed 50 percent of the
duty cycle. Typical applications include the following
examples: agricultural tractors, harvesters and
combines, off-highway trucks, fire pumps, blast hole
drills, rock curshers, wood chippers with high torque
rise and oil field hoisting.
D Rating – This rating is used when rated power is
required for periodic overloads. The maximum
horsepower and the rpm of the engine can be utilized
continuously for a maximum of 30 minutes. This is
followed by one hour of operation at the C rating. The
engine should be run at full load. The engine should
not exceed 10 percent of the duty cycle. Typical
applications include the following examples: offshore
cranes, runway snow blowers, water well drills,
portable air compressors and fire pump certification
power.
E Rating – This rating is used when rated power is
required for a short time for initial starting or for
sudden overload. The rating is also used for
emergency service when standard power is not
SEBU8312-03 93
Reference Information Section
Engine Ratings